1. 3GPP SCEF Interworking Discussions
Group Name: TP 19.3
Source:
InterDigital: Paul Russell, Jr., Mike Starsinic,
NEC Corporation: Norio Uchida, Ataru Kobayashi,
NEC Europe LTd.: Joerg Swetina,
Meeting Date: October 20th, 2015
Agenda Item: 3GPP R13 Interworking

2. Background Information
At TP18 3GPP SCEF Interworking options were discussed for oneM2M Work Item # 0037: 3GPP_Rel13 Interworking
ARC R03
ARC
ARC
Two Architecture options were discussed
Option #1 – IN-CSE provides SCEF functionality and interfaces directly with the 3GPP network
Option #2 – IN-CSE interfaces with the SCEF using OMA defined APIs
The goal of this contribution is to continue discussions on how to support SCEF in oneM2M architecture and to clarify terminology a bit to help reduce confusion.

3. Background - Option 1 Ref. ARC-2015-2157
NSSE: Network Service Exposure, Service Execution and Triggering

4. Background - Option 2 Ref. ARC-2015-2157
NSSE: Network Service Exposure, Service Execution and Triggering

5. Existing oneM2M Terms
TS-0001 defines 3 main terms for interworking with underlying networks
The Network Service Exposure, Service Execution and Triggering (NSSE) CSF manages communications with the Underlying Networks for accessing network service functions over the Mcn reference point. The NSSE CSF uses the available/supported methods for service "requests" on behalf of AEs. The NSSE CSF shields other CSFs and AEs from the specific technologies and mechanisms supported by the Underlying Networks.
The network service functions provided by the Underlying Network include service functions such as, but not limited to, device triggering, small data transmission, location notification, policy rules setting, location queries, IMS services, device management. Such services do not include the general transport services.
Underlying Network Services Entity (NSE): A Network Services Entity provides services from the underlying network to the CSEs. Examples of such services include device management, location services and device triggering. No particular organization of the NSEs is assumed.
Mcn Reference Point - Communication flows between a Common Services Entity (CSE) and the Network Services Entity (NSE) cross the Mcn reference point. These flows enable a CSE to use the supported services (other than transport and connectivity services) provided by the NSE.

6. Confusion
Per TS :
The SCEF is always part of the Trust Domain.
The AS/SCS (IN-CSE) may, or may not, be part of the trust domain.
Depending on the Deployment Model, the oneM2M Interworking Terms do not consistently Map to the 3GPP Interworking Architecture
The oneM2M Architecture is good, but the definition of some terms (NSSE, NSE and Mcn) should be modified or clarified based on SCEF deployment model to avoid confusion.

7. Clarifications to Option #1
In this case, a single company operates both the NSE and IN-CSE (3GPP SCS). The company is a trusted business partner (in 3GPP TS23.682) which provides SCEF functionality.
Operator Trust Domain
NSE
MN-CSE
3GPP NW
CSE
Mcc
Network
Entities
(HSS, MME, MTC-IWF, PCRF)
IN-CSE (SCS)
NSSE CSF
SCEF
API
Mca
IN-AE
Some functions in the 3GPP NW are NSEs.
SCEF is deployed as the oneM2M NSSE CSF within the IN-CSE
SCEF northbound interface (API) is made available to the rest of the IN-CSE. The IN-CSE may make some or all API’s available to other CSE’s and AE’s.
SCEF southbound interfaces is oneM2M Mcn reference point and is bound to 3GPP defined interfaces (e.g. Rx, Tsp, etc.)

8. Clarifications to Option #2
Operator Trust Domain
NSSE CSF functionality defined by oneM2M
SCEF southbound Interface made up of 3GPP defined interfaces (e.g. Rx, Tsp, etc.) are out of scope for oneM2M
NSE
CSE
IN-CSE (SCS)
IN-AE
Mcn
3GPP NW
API
NSSE
CSF
Multiple IN-CSEs could interface to a single SCEF
Network
Entities
(HSS, MME, MTC-IWF, PCRF)
SCEF
IN-CSE (SCS)
CSE
IN-AE
NSEE
CSF
API
Mcn
The SCEF may be deployed in a standalone manner. In this type of deployment the SCEF may be operated by the Mobile Network Operator or a trusted party. The trusted party may be a third party other than the IN-CSE operator. From the CSE’s point of view, the SCEF and the network entities that it connects to can collectively be considered an NSE.
SCEF northbound interface API (e.g. OMA APIs) is bound to oneM2M Mcn reference point.